package asynqmon

import (
	"fmt"
	"net/http"

	"github.com/go-redis/redis/v8"
	"github.com/gorilla/mux"

	"github.com/hibiken/asynq"
)

// MiddlewareFunc helps chain http.Handler(s).
type MiddlewareFunc func(http.Handler) http.Handler

type APIOptions struct {
	RedisConnOpt         asynq.RedisConnOpt
	Middlewares          []MiddlewareFunc
	PayloadFormatter     PayloadFormatter
	StaticContentHandler http.Handler
}

type API struct {
	router  *mux.Router
	closers []func() error
}

func (a *API) ServeHTTP(w http.ResponseWriter, r *http.Request) {
	a.router.ServeHTTP(w, r)
}

func NewAPI(opts APIOptions) *API {
	rc, ok := opts.RedisConnOpt.MakeRedisClient().(redis.UniversalClient)
	if !ok {
		panic(fmt.Sprintf("asnyqmon.API: unsupported RedisConnOpt type %T", opts.RedisConnOpt))
	}
	i := asynq.NewInspector(opts.RedisConnOpt)
	return &API{router: muxRouter(opts, rc, i), closers: []func() error{rc.Close, i.Close}}
}

func (a *API) Close() error {
	for _, f := range a.closers {
		if err := f(); err != nil {
			return err
		}
	}

	return nil
}

func muxRouter(opts APIOptions, rc redis.UniversalClient, inspector *asynq.Inspector) *mux.Router {
	router := mux.NewRouter()

	var pf PayloadFormatter = defaultPayloadFormatter
	if opts.PayloadFormatter != nil {
		pf = opts.PayloadFormatter
	}

	for _, mf := range opts.Middlewares {
		router.Use(mux.MiddlewareFunc(mf))
	}

	api := router.PathPrefix("/api").Subrouter()
	// Queue endpoints.
	api.HandleFunc("/queues", newListQueuesHandlerFunc(inspector)).Methods("GET")
	api.HandleFunc("/queues/{qname}", newGetQueueHandlerFunc(inspector)).Methods("GET")
	api.HandleFunc("/queues/{qname}", newDeleteQueueHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}:pause", newPauseQueueHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}:resume", newResumeQueueHandlerFunc(inspector)).Methods("POST")

	// Queue Historical Stats endpoint.
	api.HandleFunc("/queue_stats", newListQueueStatsHandlerFunc(inspector)).Methods("GET")

	// Task endpoints.
	api.HandleFunc("/queues/{qname}/active_tasks", newListActiveTasksHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/queues/{qname}/active_tasks/{task_id}:cancel", newCancelActiveTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/active_tasks:cancel_all", newCancelAllActiveTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/active_tasks:batch_cancel", newBatchCancelActiveTasksHandlerFunc(inspector)).Methods("POST")

	api.HandleFunc("/queues/{qname}/pending_tasks", newListPendingTasksHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/queues/{qname}/pending_tasks/{task_id}", newDeleteTaskHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/pending_tasks:delete_all", newDeleteAllPendingTasksHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/pending_tasks:batch_delete", newBatchDeleteTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/pending_tasks/{task_id}:archive", newArchiveTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/pending_tasks:archive_all", newArchiveAllPendingTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/pending_tasks:batch_archive", newBatchArchiveTasksHandlerFunc(inspector)).Methods("POST")

	api.HandleFunc("/queues/{qname}/scheduled_tasks", newListScheduledTasksHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/queues/{qname}/scheduled_tasks/{task_id}", newDeleteTaskHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:delete_all", newDeleteAllScheduledTasksHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:batch_delete", newBatchDeleteTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks/{task_id}:run", newRunTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:run_all", newRunAllScheduledTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:batch_run", newBatchRunTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks/{task_id}:archive", newArchiveTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:archive_all", newArchiveAllScheduledTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/scheduled_tasks:batch_archive", newBatchArchiveTasksHandlerFunc(inspector)).Methods("POST")

	api.HandleFunc("/queues/{qname}/retry_tasks", newListRetryTasksHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/queues/{qname}/retry_tasks/{task_id}", newDeleteTaskHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/retry_tasks:delete_all", newDeleteAllRetryTasksHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/retry_tasks:batch_delete", newBatchDeleteTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks/{task_id}:run", newRunTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks:run_all", newRunAllRetryTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks:batch_run", newBatchRunTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks/{task_id}:archive", newArchiveTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks:archive_all", newArchiveAllRetryTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/retry_tasks:batch_archive", newBatchArchiveTasksHandlerFunc(inspector)).Methods("POST")

	api.HandleFunc("/queues/{qname}/archived_tasks", newListArchivedTasksHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/queues/{qname}/archived_tasks/{task_id}", newDeleteTaskHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/archived_tasks:delete_all", newDeleteAllArchivedTasksHandlerFunc(inspector)).Methods("DELETE")
	api.HandleFunc("/queues/{qname}/archived_tasks:batch_delete", newBatchDeleteTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/archived_tasks/{task_id}:run", newRunTaskHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/archived_tasks:run_all", newRunAllArchivedTasksHandlerFunc(inspector)).Methods("POST")
	api.HandleFunc("/queues/{qname}/archived_tasks:batch_run", newBatchRunTasksHandlerFunc(inspector)).Methods("POST")

	api.HandleFunc("/queues/{qname}/tasks/{task_id}", newGetTaskHandlerFunc(inspector, pf)).Methods("GET")

	// Servers endpoints.
	api.HandleFunc("/servers", newListServersHandlerFunc(inspector, pf)).Methods("GET")

	// Scheduler Entry endpoints.
	api.HandleFunc("/scheduler_entries", newListSchedulerEntriesHandlerFunc(inspector, pf)).Methods("GET")
	api.HandleFunc("/scheduler_entries/{entry_id}/enqueue_events", newListSchedulerEnqueueEventsHandlerFunc(inspector)).Methods("GET")

	// Redis info endpoint.
	switch c := rc.(type) {
	case *redis.ClusterClient:
		api.HandleFunc("/redis_info", newRedisClusterInfoHandlerFunc(c, inspector)).Methods("GET")
	case *redis.Client:
		api.HandleFunc("/redis_info", newRedisInfoHandlerFunc(c)).Methods("GET")
	}

	router.PathPrefix("/").Handler(opts.StaticContentHandler)
	return router
}